1 . You look up at the sky on a clear and dark night, you’ll see more stars than your eyes can count. Most of these stars have planets, similar to our own, orbiting them. With so many celestial bodies floating out in space, you can’t help but question whether other forms of life exist in the universe. And if that’s the case, is it possible to contact them?

Science is still somewhat divided on this issue. Currently, no evidence exists to suggest that intelligent life exists elsewhere in the universe. Yet with an estimated one trillion planets in our galaxy alone, it seems highly likely that Earthlings aren’t the only intelligent creatures out there. Some claim that life can only develop under perfect circumstances, and Earth is perhaps the only example of this. Other scientists object to this claim, and point out that even on Earth, life can find a way under the most extreme circumstances.

Some people believe that aliens have already visited our planet, but this information is being kept secret by governments. The most famous incident of this kind occurred in Roswell, New Mexico in 1947. On that date, many residents reported seeing an unusual flying disc streak through the sky, before it crashed in a field. When the military heard about the crash, they quickly sealed off the area. A few hours later, the army base announced that it had recovered a flying disk. Shortly after, this statement was retracted and it was said that it was a weather balloon that crashed. However, years later one local mortician even claimed that the military had him secretly perform an autopsy on a dead alien body.

Others believe that there certainly are other life forms out there, but the distance between us is too great. Even if we could somehow create a spaceship that travels at the speed of light, it would still probably take several lifetimes to reach them. Then again, we might never have to do this if aliens reach us first.

1. Why do some scientists think there is life on other planets?

A．Because an unusual flying disc was ever witnessed.

B．Because life exists despite extreme conditions as those on the Earth do.

C．Because the government’s statement seemed suspicious.

D．Because there are a great number of planets in the universe.

2. What does the underlined word “retracted” in paragraph 3 mean?

A．Examined again to guarantee the correctness.	B．Emphasized again to persuade people.
C．Formally taken back what has been said.	D．Seriously criticized due to poor evidence

3. Which of the following might be the best title for the text?

A．Are we alone in the universe?	B．Is it possible to contact aliens?
C．Intelligent life in the universe.	D．Planets floating out in space.

4. How does the author sound in the passage?

A．Objective.

B．Humorous.

C．Cautious.

D．Anxious.

2 . Like a phoenix (凤凰), some stars may burst to life covered in “ash,” rising from the remains of stars that had previously passed on.

Two fireballs covered in carbon and oxygen, ashy byproducts of helium fusion (氦聚变), belong to a new class of stars, researchers report in the March Monthly Notices. Though these burning objects are not the first stars found covered in carbon and oxygen, they are the first discovered to have helium-burning cores.

“That merger (并合) tells you the star must have evolved differently,” says study author Nicole Reindl.

The stars may have formed from the merger of two white dwarfs (白矮星), the remaining hearts of stars that exhausted their fuel, Reindl further explains. One of the two was rich in helium, while the other contained lots of carbon and oxygen. These two white dwarfs had already been orbiting one another, but gradually drew together. Eventually the helium-rich white dwarf “ate” its partner, leaving carbon and oxygen all over its surface, just as a messy child might get food all over their face.

Such a merger would have produced a star covered in carbon and oxygen to burn nuclear fusion in its core again, says Tiara Battich, a German astrophysicist.

To test this idea, Battich copied the evolution, death and eventual merger of two stars on his computer and simulated (模拟) the process. He found that putting together a carbon-and-oxygen-rich white dwarf and a more massive helium one could explain the compositions of the two stars observed by Reindl and her colleagues.

“But this should happen very rarely,” Battich says. In most cases the opposite should occur, because carbon-oxygen white dwarfs are usually the more massive ones. For the rarer case to occur, two stars slightly more massive than the sun must have formed at just the right distance and the right time.

"The origins story Battich proposes demands a very specific and unusual set of circumstances, " says Simon Blouin, a Canadian astrophysicist. “But in the end, it makes sense.”

1. What’s the newest discovery of the merger of two stars?

A．It produces a mass of helium ash.

B．It possesses a helium-burning core.

C．It is covered in carbon and oxygen.

D．It makes an oxygen atmosphere for life.

2. How did Battich prove his assumption of the merger?

A．By co-working with Rcindl’s team.

B．By making astronomic observations.

C．By building models on his computer.

D．By testing the two stars’ compositions.

3. The underlined phrase “the opposite” means ________.

A．the carbon-oxygen white dwarf “ate” the helium one

B．the helium white dwarf “ate” the carbon-oxygen one

C．helium white dwarfs are usually the more massive ones

D．carbon-oxygen white dwarfs are usually the more massive ones

4. What’s the main idea of the text?

A．The formation of stars makes sense.

B．The burning of stars brings them to life.

C．Stars inspire scientists to reflect on the universe.

D．Star mergers can unfold in more than one way.

3 . Interesting Space Facts

As time goes by, technological advancements have made us learn more facts about space in the past century than in all time before that. We’ve already searched the universe for the most amazing space facts, including facts about the planets in our solar system, moons, the Milky Way and beyond!     1    

The highest mountain discovered is the Olympus Mons, which is located on Mars. It is 16 miles high, making it nearly 3 times higher than Mount Everest.    2     That’s the size of Arizona !

The sun weighs about 330,000 times more than Earth.    3     In fact, the sun is so huge that it contains 99.85% of all mass in our solar system.

Footprints left on the moon won’t disappear as there is no wind. But wait a minute.

    4     Well, it actually wasn’t blowing. That blowing you see is because of a telescopic horizontal rod (望远镜水平杆) that the astronauts were struggling to remove from the flag’s top.

    5     This is due to the lack of gravity in space causing the vertebrae (椎骨) to expand a little. However, this extra height is lost when they re-enter the earth’s atmosphere and are affected by the earth’s gravity again.

A．We’re pretty sure they will make you interested!

B．New discoveries will no longer be made in the future.

C．It is so large that it can contain about 1,300,000 Earths!

D．Not only is it tall, but it’s 114,000 square meters as well.

E．All these space facts may not be true at the time of writing.

F．Astronauts can grow about two inches in height when in space.

G．If there’s no wind to blow them away, then why is the flag blowing?

4 . 阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

Do stars only appear at night? The answer is no. Venus(金星)is the only star     1     can be seen in daytime. It is the second     2    (bright) natural object, behind the earth's moon, in the night sky. Why is it so bright? First of all, Venus is the closest planet to the earth. Besides, it     3    (cover) with highly reflective clouds, which reflect about 70 percent of the sunlight     4    (strike) it.

If Venus is so bright and close to us, isn't it a better choice for human     5    (explore) than Mars? It is closer to the earth than Mars and it's closer to the earth     6     size. The closer distance to the sun means solar power would be easier     7    (generate) as well.

    8    , with a temperature of about 465°C on the surface. Venus is the hottest planet in our solar system! But scientists never give up and     9    (create) new computer equipment that can stand 480°C recently.     10     they expect next is to send a probe(探测器)to Venus by 2025.

6 . 阅读下面材料，在空白处填入适当的内容（1 个单词）或括号内单词的正确形式。

Scientists showed the first-ever photograph of a black hole on April 10, 2019. The photo     1     (show) at press conferences held at the same time in Shanghai, Taipei, Tokyo, Washington DC, Brussels and Santiago. In the image, a central dark region is surrounded by a ring of light that looks     2     (bright) on one side than the other side.

The photo is the product of observations    3     (make) in April 2017 by the Event Horizon Telescope (EHT). The EHT is     4     global network of telescopes. Over 200     5     (research) were involved in the project. In their more than a decade’s attempt    6     (capture) an image of a black hole, scientists combined the power of eight radio telescopes around the world. This    7     (effective) creates a virtual telescope around the same size as the Earth itself.

This image reveals the black hole at the center of Messier 87 (M87), a massive galaxy in the nearby Virgo galaxy cluster(室女星系团). This black hole lies about 55 million lightyears from the Earth and its mass is 6.5 billion times    8     of the sun.

“We have seen what we thought was unseeable,” said Sheperd Doeleman, a Harward astronomer and project director of the EHT. It closely resembles what astronomers have expected, based on Einstein’s general theory of relativity. Since Einstein published this theory in 1915,     9     first predicted the existence of black holes, no one really    10     (see) what it looks like. This captured image is the first direct visual evidence that black hole exist.

9 . For years, planet-hunters have been searching for a planet other than Earth that can support life. They may have found one.

The planet is the sixth found orbiting a star called Gliese 581. Steven Vogt, one of the scientists involved, expects the new planet to have water. On Earth, when we find water, we find life.     1    

A planet that can support life has to be just the right size for its system and just the right distance from its star. Some planets orbit so close to their stars that they’re much too hot for liquid water—or for life as we know it.     2    

But a right-sized planet that's neither too close nor too far might be just right for water. Gliese 581 is probably just right. It is about three times as huge as Earth.     3     Because it’s so close, one side of it always faces its star, and the other side is always dark.

The new planet is 20 light years away, which is as far as 250 million trips to the Moon and back.     4     Only light can go that fast. So even at the fastest speed we could manage, it would take a spaceship from Earth more than 200 years to go that far.     5     But that doesn’t mean we can’t study it. Thanks to powerful new telescopes and new techniques for searching the skies, scientists can learn a lot about distant planets without even leaving Earth.

Gliese 581 is an exciting discovery—and astronomers are likely to find more soon, thanks to new, powerful telescopes specifically designed to look for planets.

A．We can’t travel at the speed of light.

B．It’s pretty hard to imagine that water wouldn't be there.

C．Human beings won’t be visiting this planet any time soon.

D．So scientists looking for life on other planets look for water first.

E．It orbits its star so closely that it goes all the way around in only 37 days.

F．Astronomers will probably find more potential life-supporting planets soon.

G．Other planets keep their distance from the stars—where they’re too cold to have water or life.